1. Field of the Invention
The invention relates to a semiconductor device and more particularly to a semiconductor diode with reduced power loss.
2. Description of the Related Art
A semiconductor diode is a well known electronic component that restricts the direction of flow of charge carriers. The semiconductor diode allows an electric current to flow in an intended direction, but substantially blocks current flow in an opposite direction with respect to the intended direction. Without diodes, most electronic devices would simply not operate.
The most common semiconductor diodes are p-n junction diodes made of semiconductor material, such as silicon, Gallium Arsenide (GaAs) or silicon carbide (SiC), with impurity elements introduced therein to modify the operating characteristics thereof. P-n junction diodes are widely used for low voltage switching, power supply, power convert and related applications. As is well known in the art, such a p-n junction diode blocks current when the cathode (n-side) is made positive with respect to the anode (p-side) until the cathode voltage is high enough to cause a breakdown. In the reverse bias mode of operation, the current from the cathode to the anode is very low and is called leakage current. When the anode is made positive with respect to the cathode, the mode of the operation is referred to as a forward bias (the voltage across the diode is referred to as the forward bias voltage). The current from the anode to the cathode is increased with increased forward bias voltage. The effect of this rise in current, switches the diode to an ON state, when a threshold voltage (or turn on voltage) is reached. When the turn voltage is surpassed, current increases significantly.
Typically, diodes require a turn on voltage of about 0.7 Volts, and diodes dissipate power in proportion to this forward voltage. Many household electronic devices, such as televisions, microwave ovens or the likes, are powered by household voltages and thus they can tolerate a power loss of the diodes in the circuit. This power loss, however, cannot be tolerated as well by battery powered electronic devices, such as a laptop computer, a mobile phone, a digital camera, and the like because this power loss directly reduces battery life, thereby impacting the usability of the electronic device. As sizes of semiconductor devices continuously shrink, along with increased device density in the integrated circuits, the power loss problem for integrated circuits worsens.
Accordingly, there is a need to develop a novel semiconductor diode design which is capable of mitigating the aforementioned problems.